Link aggregation, sometimes called trunking, combines a set of links so that they behave like a single link. A combined set of links is called an aggregated link, a virtual link, or a trunk. A port that participates in link aggregation is called an aggregation port.
The capability to aggregate links affords important benefits:
A high-capacity link can be set up between a pair of systems by combining a group of links.
The procedure improves network availability. The failure of one under-lying link in a group of links causes a reduction in available bandwidth, but the aggregated link continues to function.
In the past, it was common to install extra LAN links for backup purposes.A backup link would be idle unless ...